A 10-week feeding trial was conducted to evaluate the effect of dietary methionine (MET) on the growth performance, lipid metabolism and liver antioxidant function in juvenile large yellow croaker (Larimichthys crocea) fed with high lipid diets (HLDs). Large yellow croaker with an initial average weight of 8.59 g, were fed with basic HLD (lipid level at 18%, HL), basic HLD supplemented with 0.6% MET (HL/L-MET) and basic HLD supplemented with 1.2% MET (HL/H-MET). Results indicated that dietary MET did not affect weight gain, specific growth rate and feed efficiency ratio (P > 0.05). The MET supplementation in large yellow croaker also did not affect the content of total lipid in whole body (HL = 9.57, HL/L-MET = 8.92 and HL/H-MET = 8.71%), liver (7.34, 16.68 and 14.37%) and muscle (10.87, 12.11 and 9.94%) (P > 0.05). However, MET supplementation reduced the size and number of liver lipid droplets as dietary MET increased. Meanwhile, supplementation of MET in HLDs reduced serum total cholesterol (2.65, 2.14 and 1.91 mmol/L), low-density lipoprotein-cholesterol (0.27, 0.21 and 0.16 mmol/L) and triglyceride (4.80, 2.43 and 1.96 mmol/L) (P < 0.05), but increased serum high-density lipoprotein-cholesterol (0.68, 0.77 and 0.83 mmol/L) (P < 0.05). Dietary MET upregulated significantly the mRNA expression of genes related to mitochondrial fatty acid β-oxidation (PPARα and CPT1) and ER stress (GRP78, ATF6α and CHOP) (P < 0.05). Furthermore, feeding fish with MET diets reduced serum alanine transaminase and aspartate transaminase activities, serum and liver malondialdehyde content, and liver 8-hydroxydeoxyguanosine level. Interestingly, feeding fish with MET diets increased liver total antioxidant capacity activity (P < 0.05). In conclusion, dietary MET improved lipid metabolism and increased antioxidant capacity in the liver, but did not affect growth performance in juvenile large yellow croaker fed with HLDs.

进行了为期10周的喂养试验，以评估日粮蛋氨酸（MET）对高脂日粮（HLDs）喂养的大黄鱼（Larimichthys crocea）的生长性能，脂质代谢和肝脏抗氧化功能的影响。初始平均重量为8.59 g的大型黄花鱼饲喂碱性HLD（脂质水平为18％，HL），补充0.6％MET的碱性HLD（HL / L-MET）和补充1.2％MET的碱性HLD（ HL / H-MET）。结果表明，日粮MET不会影响体重增加，比生长速度和饲料利用率（P  > 0.05）。大黄鱼中的MET补充也不会影响全身的总脂质含量（HL = 9.57，HL / L-MET = 8.92和HL / H-MET = 8.71％），肝脏（7.34 ，16.68 14.37和％）和肌肉（10.87 ， 12.11和9.94％）（P>  0.05）。然而，随着膳食MET的增加，MET补充剂减少了肝脂质滴的大小和数量。同时，在HLD中补充MET可降低血清总胆固醇（2.65、2.14和1.91 mmol / L），低密度脂蛋白胆固醇（0.27、0.21和0.16 mmol / L）和甘油三酸酯（4.80、2.43和1.96 mmol / L） （P  <0.05），但血清高密度脂蛋白胆固醇（0.68、0.77和0.83 mmol / L）增加（P  <0.05）。日粮MET显着上调了线粒体脂肪酸β-氧化（PPARα和CPT1）和ER应激（GRP78，ATF6α和CHOP）相关基因的mRNA表达（P <0.05）。此外，用MET饲料喂养鱼类会降低血清丙氨酸转氨酶和天冬氨酸转氨酶活性，血清和肝脏丙二醛含量以及肝脏8-羟基脱氧鸟苷水平。有趣的是，用MET饲料喂养鱼类可以增加肝脏的总抗氧化能力（P  <0.05）。总之，日粮MET改善了肝脏的脂质代谢并增加了抗氧化能力，但并未影响饲喂HLD的大型黄花鱼的生长性能。